Effect of balanced fertilization on production of pineapple in Hainan

The study was aimed to further fine-tune the optimal fertilizer rates determined in the previous two years of field experiments on chili pepper, one of the most widely grown vegetables in winter in Hainan, China. In 2011, the optimal rates of N and P were determined to be 300 and 60 kg/ha for high yield chili production. This year, six K rates (0, 60, 120, 180, 240, and 300 kg K₂O/ha) were evaluated. The source, timing, and placement of fertilizers and field management remained the same as in 2010 and 2011.
Results showed that chili pepper yields increased significantly with increasing K rates, but leveled off at 240 kg K₂O/ha. This K rate, in combination with the optimal N and P, produced 552 kg/ha (18%) more chili pepper yield and US$284 more economic return than the K-omission treatment. Furthermore, this treatment also achieved higher K use and agronomic efficiencies than any other treatments. Thus, based on the data from three years of the trial, 300 kg N, 60 kg P₂O₅ and 240 kg K₂O/ha can be recommended as the optimal nutrient management strategy to chili growers in Hainan. Further, if a soil test indicates a high soil P, fertilizer P can be omitted from the fertilizer program for every other crop season. Hainan-08